2*10^3-1.9*10^2. adding and subtracting numbers in notation

Find the value of x for which abcd must be a parallelogram -9-6x x-30

Galen sold tickets of his church’s carnival for a total of $2,820. children’s tickets cost $3 each and adult tickets cost $5 each. the number of children’s tickets sold was 30 more than 3 times the number of adult tickets slod. how many children’s ticket and how many adult tickets did he sell?

65% of students in your school participate in at least one after school activity. if there are 980 students in you school, how many do not participate in an after school activity?